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/* alias.c
*
* Alias expansion and maintenance for lafe.
*/
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include "lafe.h"
static int aliases=0;
static char **key=NULL; /* alias names */
static char **value=NULL; /* alias definitions */
static int width=0; /* size of largest alias key */
static void print_aliases() {
int i;
for (i=0;i<aliases;i++) {
printf("%-*s %s\n",width,key[i],value[i]);
}
printf(" %d aliases\n",aliases);
return;
}
/* look up name in alias database and return index. Should do a
* binary search. Returns -1 if name is not found. */
static int find_alias(char *name) {
int i;
for (i=0;i<aliases;i++) {
if (!strcmp(name,key[i])) return i;
}
return -1;
}
static void remove_alias(char *name) {
int i;
i = find_alias(name);
if (i>=0) {
free(key[i]);
free(value[i]);
aliases--;
key[i]=key[aliases];
value[i]=value[aliases];
} else {
printf("%s not defined\n",name);
}
}
static void define_alias(char *name,char *definition) {
int i;
int w;
w=strlen(name);
if (w>width) width=w;
i=find_alias(name);
if (i>=0) {
free(value[i]);
value[i]=strdup(definition);
} else {
key=realloc(key,(aliases+1) * sizeof(*key));
value=realloc(value,(aliases+1) * sizeof(*value));
key[aliases]=strdup(name);
value[aliases]=strdup(definition);
aliases++;
}
}
/* alias expansion. Tokenizes arg and adds tokens to environment $1 $2 .... */
/* not finished */
static void tokenize(char *arg) {
int start,end;
char c,buffer[8];
int i;
putvar("*",arg);
/* put each fragment of arg into environment variables */
i=0;
for (start=0;arg[start];start++) {
if (!isspace(arg[start])) {
for (end=start+1;arg[end] && !isspace(arg[end]);end++) ;
c=arg[end];
arg[end]=0;
sprintf(buffer,"%d",++i);
putvar(buffer,arg+start);
arg[end]=c;
start=end;
}
}
sprintf(buffer,"%d",++i);
clearvar(buffer);
}
/* line must be individually malloced. If the alias is expanded, line will
be freed by expand_alias, and a new line returned */
char *expand_alias(char *line) {
int i,j,k;
char *alias,*semi;
for (i=0;line[i] && isspace(line[i]);i++) ;
for (j=i;line[j] && !isspace(line[j]);j++) ;
/* attempt to locate the alias index for this line */
{
char c;
c=line[j]; line[j]=0;
k=find_alias(line+i);
line[j]=c;
}
/* no alias found, so return line */
if (k<0) return line;
/* expand ;'s in alias */
alias=strdup(value[k]);
semi=strchr(alias,';');
while (semi) {
*semi='\n';
semi=strchr(semi+1,';');
}
/* advance j to next character */
for (;line[j] && isspace(line[j]);j++) ;
/* if there are $'s in the alias, fill variables and return alias value */
if (strchr(alias,'$') || strchr(alias,'\n')) {
tokenize(line+j);
free(line);
return alias;
/* otherwise, replace the first word and append arguments */
} else {
int len;
char *newline;
len=strlen(alias);
newline=malloc(len+strlen(line+j)+2);
strcpy(newline,alias);
newline[len]=' ';
strcpy(newline+len+1,line+j);
free(line);
free(alias);
return newline;
}
}
/* no arguments prints the alias database.
* one argument delete the alias for that argument.
* two arguments defines a new alias.
*/
void alias(char *line) {
int i,j,k;
i=0;
/* print alias database */
if (!line || !*line) {
print_aliases();
return;
}
/* alias name starts at i, ends at j. Def starts at k. */
/* get name of new or old alias */
for (j=i;line[j] && !isspace(line[j]);j++) ;
/* skip whitespace */
for (k=j;line[k] && isspace(line[k]);k++) ;
/* delete definition of name */
if (!line[k]) {
line[j]=0;
remove_alias(line+i);
return;
}
line[j]=0;
define_alias(line+i,line+k);
}
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